Polypropylene is utilized extensively across a wide range of industries in a variety of product forms, such as fibers, films and three-dimensional structures. An important application for polypropylene is container, especially for food and beverages. Polypropylene material often are selected for use in food and beverage packs and closures as they are inexpensive, lightweight, easily moulded and resistant to impact.
Polyethylene material is also used in food and beverage packs and closures & in films.
Polypropylene or polyethylene do have certain undesirable attributes for example, they frequently contribute off-taste to the packaged product such as liquids. This off-taste may be contributed by unsaturated slip agents such as erucamide. Slip agents are used to reduce the force required to remove the closure from a bottle or package.
It is well known in the art to make caps with erucamide as a slip agent which facilitates unscrewing of the cap. However, erucamides are ethylenically-unsaturated amides that react with ozone that is used for sterilization, thereby creating aldehyde off-tastes that adversely affect beverage products such as carbonated water and soft drinks.
U.S. Pat. No. 4,785,042 (assigned to M/s Idemitsu Petrochemical Co. Ltd.) discloses stearylbehenamide for improving slipping and sliding properties of polyethylene resins to be used in films. However, it does not disclose use of a mixture of linear saturated fatty amides and glycerol mono stearate.
U.S. Pat. No. 5,948,846 (assigned to M/s Solvay) discloses use of zeolite in polyolefin compositions for improving organoleptic properties and good slip.
U.S. Pat. No. 6,806,313 (assigned to M/s W. R. Grace & Co.) discloses use of saturated amides and an oxidized polyethylene as slip aid for a matrix polymer, copolymer or blend thereof. However, the use of linear saturated fatty amides with glycerolmonostearate has not been disclosed.
Journal of the American Oil Chemists' Society (1955), 32, 354-6 discloses esteramides of certain aminoalcohols as plasticizers.
United States Published Patent Application No. 20120101201 (assigned to M/s Croda International PLC) teaches saturated branched hydrocarbon chain fatty amides as mold release agents.
U.S. Pat. No. 6,846,863 (assigned to M/s Solvay Polyolefins Europe-Belgium) discloses use of saturated fatty acid amide viz. behenamide as slip agent in polyolefin screw caps for bottles. However, the use of saturated amides, such as behenamide, while avoiding the off-taste problem, tend to be less effective as slip agents because it is believed that they migrate slowly to the surface of the matrix polymer and thereby are less efficacious in providing a low-friction surface.
None of the above references teach use of mixture of linear saturated fatty amides and glycerol monostearate as slip agent in polypropylene cap composition for reducing torque release and providing improved organoleptic properties of liquid stored in liquid containers sealed with the polypropylene cap when compared with erucamide.
Also, none of the above references teach use of mixture of linear saturated fatty amides and glycerol monostearate as slip agent in polyethylene cap composition for reducing torque release and providing improved organoleptic properties of liquid stored in liquid containers sealed with the polyethylene cap when compared with erucamide.